USB stack / configuration 0

[Bernd Walter]

On Wed, Jan 07, 2004 at 04:05:15PM +1030, Daniel O'Connor wrote:
> On Tuesday 06 January 2004 18:47, Bernd Walter wrote:
> > > When setting a USB device to configuration number USB_UNCONFIG_NO (i.e.
> > > 0), the device goes into an unconfigured state with an invalid
> > > dev->cdesc. How does one then leave this unconfigured state and
> > > reconfigure the device to accept configuration changes? (all
> > > USB_SET_CONFIG changes are currently refused after going into
> > > configuration 0 - I'm not sure if this is the desired behaviour or a bug)
> >
> > I have to read the docs first bevor making a qualified comment about
> > this.
> 
> I'm not 100% sure if this applies, but..
> There are certainly situations where you want to reenumerate the USB devices, 
> for example there are a number of devices which have no real firmware - they 
> expect to be programmed by the PC then reset and reenumerated after being 
> plugged in.

Different story.

> I have such a device (M-Audio Mobile Pre USB) and I have modified USB audio 
> code which works except that you need to manually reset the device without 
> removing power (which is done by partially removing and then reinserting the 
> USB connector).

Bad device - it would have been so easy add an single transitor to do
this automaticaly.
Nevertheless USB_UNCONFIG_NO can't help you here.
What you need to do is toggling the hub port if the device is to
stupid to detach/reattach on his own.

-- 
B.Walter                   BWCT                http://www.bwct.de
ticso at bwct.de                                  info at bwct.de